'\" e
'\"! eqn | mmdoc
'\"macro stdmacro
.ds Vn Version 1.2
.ds Dt 24 September 1999
.ds Re Release 1.2.1
.ds Dp Jan 14 18:30
.ds Dm 01 indexmask
.ds Xs 54319 4 indexmask.gl
.TH GLINDEXMASK 3G
.SH NAME
.B "glIndexMask
\- control the writing of individual bits in the color index buffers

.SH C SPECIFICATION
void \f3glIndexMask\fP(
GLuint \fImask\fP )
.nf
.fi

.EQ
delim $$
.EN
.SH PARAMETERS
.TP \w'\f2mask\fP\ \ 'u 
\f2mask\fP
Specifies a bit mask to enable and disable the writing of individual bits
in the color index buffers.
Initially, the mask is all 1's.
.SH DESCRIPTION
\%\f3glIndexMask\fP controls the writing of individual bits in the color index buffers.
The least significant $n$ bits of \f2mask\fP,
where $n$ is the number of bits in a color index buffer,
specify a mask.
Where a 1 (one) appears in the mask,
it's possible to write to the corresponding bit in the color index
buffer (or buffers). 
Where a 0 (zero) appears,
the corresponding bit is write-protected.
.P
This mask is used only in color index mode,
and it affects only the buffers currently selected for writing
(see \%\f3glDrawBuffer\fP).
Initially, all bits are enabled for writing.
.SH ERRORS
\%\f3GL_INVALID_OPERATION\fP is generated if \%\f3glIndexMask\fP
is executed between the execution of \%\f3glBegin\fP
and the corresponding execution of \%\f3glEnd\fP.
.SH ASSOCIATED GETS
\%\f3glGet\fP with argument \%\f3GL_INDEX_WRITEMASK\fP
.SH SEE ALSO
\%\f3glColorMask(3G)\fP,
\%\f3glDepthMask(3G)\fP,
\%\f3glDrawBuffer(3G)\fP,
\%\f3glIndex(3G)\fP,
\%\f3glIndexPointer(3G)\fP,
\%\f3glStencilMask(3G)\fP
